Slashdot videos: Now with more Slashdot!

View

Discuss

Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).

Nerval's Lobster writes "NASA's Mars Reconnaissance Orbiter has sent 200 terabits of scientific data all the way back to Earth over the past seven years. That data largely comes from six instruments aboard the craft, and doesn't include the information used to manage the equipment's health. That 200-terabit milestone also surpasses the ten years' worth of data returned via NASA's Deep Space Network from all other missions managed by NASA's Jet Propulsion Laboratory in Pasadena, California. 'The sheer volume is impressive, but of course what's most important is what we are learning about our neighboring planet,' JPL's Rich Zurek, the project scientist for the Mars Reconnaissance Orbiter, wrote in a statement. It takes roughly two hours for the craft to orbit Mars, recording voluminous amounts of data on everything from the atmosphere to the subsurface. Thanks to its instruments, we know that Mars is a dynamic environment, once home to water. 'Mars Reconnaissance Orbiter has shown that Mars is still an active planet, with changes such as new craters, avalanches and dust storms,' Zurek added. 'Mars is a partially frozen world, but not frozen in time.' While the Orbiter's two-year 'primary science phase' ended in 2008, NASA has granted the hardware three additional extensions, each of which has resulted in additional insight into the Red Planet's secrets."

You have to do the numbers in high density 3.5" (1.44MB formatted)... so 18,222,223 disks for 25TB.

And I have no idea how you got 12.8 million (DD = 800kB or 720kB depending on formatting). Your numbers suggest 2.038MB per floppy... some HD 3.5" were marketed as "2MB" but that was *unformatted*. And the rounding error is likely from 1024 vs. 1000 multiples between kB/MB/GB/TB.

What if it's on one of those old-ass mainframes with 6-bit bytes? What if it's encoded as if it's being transmitted over an analog modem (which it might very well be encoded that way)? That uses 10-bit bytes.

Why do humans need real-time video communication on Mars? It won't be real-time. Mars is 3 light-minutes away from Earth. The best we can hope for is a 6 minute lag between you asking a question and getting an answer.

And if you're going to have a six-minute lag, pretty much the bandwidth is irrelevant. It might as well be by the cheapest way possible, i.e. audio only with the occasional static picture for the "What the hell is this in the microscope?" questions.

The sheer bandwidth is also the problem. At 6 minute latencies, you're basically introducing more and more "buffers" to ensure correct data transmission. You won't know if what you sent was received properly until six minutes later. So you have to store AT LEAST six minutes of data (more likely lots more as you will have to retransmit).

The more bandwidth you wish to buffer, the larger storage that six minutes costs you. Six minutes of audio is nothing. A few hundred Kb. Six minutes of video is more. Six minutes of HD video is more again. And so on. And everything that you store / forward costs BIG money over interplanetary scales - from the broadcasting station itself (which can't reasonably ever be upgraded) to the DSN satellies around Mars to the receiving stations on Earth, and the more you send and the more you store and the faster you want to do it, the more it costs EVERYWHERE.

And, as you state, there is NO scientific value in this. So until humans are on the planet, it's really moot. But once they are there, HD video is the least of their concerns.

This is probably why you're not Director of Planetary Exploration at NASA, by the way.

No one there? That's what they want you to think. Statistically with that volume of data being sent back there has to be petabytes of infringing content being sent TO Mars. It's a colony of space pirates. The content industry should ready their lawyers.

That 200-terabit milestone also surpasses the ten years' worth of data returned via NASA's Deep Space Network from all other missions managed by NASA's Jet Propulsion Laboratory in Pasadena, California

I'm not sure how to read that sentance. JPL manages missions, and they also manage the DSN. But missions managed at APL, GSFC, MSFC and other places *also* use the DSN.

And DSN's much older than 10 years... Voyager uses it, and it was launched in 1977.